Research

I have a broad interest in programming quantum machines (especially, Rydberg atom-based hardware) to implement quantum computing/simulation.

Research highlights:

Rydberg blockade-based gadgets: Building blocks of quantum optimization architecture,
Studying the dynamics of a single atom in optical tweezers,
Designing a moving tweezer-based digital quantum computing protocol,

Rydberg blockade-based gadgets: Building blocks of quantum optimization architecture

Rydberg atom arrays are native solvers for optimization problems. Maximum (weighted) independent set (MWIS), an NP-hard optimization problem, is encoded in the ground state of a Rydberg atom array, thanks to the Rydberg blockade, which strongly limits the number of excitations within a given volume. However, the Rydberg blockade is a distance-dependent feature, so only unit-disk or unit-ball-type MWIS problems can be directly solved by realistic quantum hardware.

Gadgets, clusters of auxiliary atoms, can effectively embed a wide range of MWIS problems. Gadgets are building blocks for quantum optimization architecture.

Topic 1: Gadget design

To effectively perform the target operation, designing gadgets is necessary. I contributed to designing the following types of gadgets:

Gadget design: For solving "quadratic unconstrained binary optimization (QUBO)" using only global driving

M. Lanthaler, K. Ender, D. Khachatryan, P. Ildefonso, A. Byun, C. Dlaska, M. Schuler, and W. Lechner,
“Quantum optimization with globally driven neutral atom arrays,”
arXiv: 2401.03902 (2026).

Gadget design: For solving "higher-order unconstrained binary optimization (HUBO)"

A. Byun, S. Jeong, and J. Ahn,
"Programming higher-order interactions of Rydberg atoms,"
Phys. Rev. A 110, 042612 (2024).

Gadget design: For solving "quadratic unconstrained binary optimization (QUBO)"

A. Byun, J. Jung, K. Kim, M. Kim, S. Jeong, H. Jeong, and J. Ahn,
"Rydberg-Atom Graphs for Quadratic Unconstrained Binary Optimization Problems,"
Adv. Quantum Technol. 7, 2300398 (2024).

Gadget design: For solving "unit-ball maximum independent set (UB-MIS) problem"

A. Byun*, M. Kim*, and J. Ahn,
"Finding the Maximum Independent Sets of Platonic Graphs Using Rydberg Atoms,"
PRX Quantum 3, 030305 (2022).

Topic 2: Error correction code

Auxiliary atoms in gadgets can serve as error-correction resources. I developed an error-detection and -correction method for a gadget-based architecture, including designing a decoder:

Error correction code: Cluster decoder for gadget-based architecture

comming soon!

Studying the dynamics of a single atom in optical tweezers

Optical tweezers "trap" a single neutral atom, meaning they apply a localized force to the atom. As a result, the atom exhibits both classical and quantum dynamics within the tweezer. I analyzed both types of dynamics and, by properly designing the time-dependent force trajectory, developed controlled paths for targeted atomic motion, including throw-and-catch operations and time-optimal transport:

Fast and reliable single-atom transport by optical tweezer based on shortcut-to-adiabaticity (STA).

S. Hwang, H. Hwang, K. Kim, A. Byun, K. Kim, S. Jeong, M. P. Soegianto, and J. Ahn, "Fast and reliable atom transport by optical tweezer," Optica Quantum 3(1), 64-71 (2025).

Throw-and-catch single-atom by optical tweezer

H. Hwang, A. Byun, J. Park, S. de Léséleuc, and J. Ahn, "Optical tweezers throw and catch single atoms,"
Optica 10(3), 401-406 (2023).

Designing a moving tweezer-based digital quantum computing protocol

Dynamic optical tweezers not only transport atoms but also implement quantum operations. Combined with a chromatically distinguishable dual-species atomic array, I developed a MAQCY scheme, a Modular Atom-array Quantum Computation with space-time hYbrid multiplexing.

A modular atom-array quantum computation with space-time hybrid multiplexing

A. Byun*, C. Lee*, E. Yoon, M. Kim, and T. H. Yoon, "MAQCY: A modular atom-array quantum computation with space-time hybrid multiplexing," arXiv:2510.02940 (2025).

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